Intel Pentium III 550E socket: Socket 370

What the Pentium III 550E is

The Intel Pentium III 550E is a 550 MHz single-core desktop processor from October 1999. It runs one P6 Coppermine core at 550 MHz with no turbo, so 1 core gives 1 thread. Cache is 256 KB of full-speed Advanced Transfer Cache with 32 KB of L1 on a 180 nm process. Power is rated at 14.5 W in a Socket 370 FC-PGA package on a 100 MHz front side bus with a 5.5x multiplier at 1.6 V.

A half-ratio lift over the 500E at a small power cost makes the 550E a steady entry pick, which is why it shipped in first-wave Coppermine towers. A Slot 1 cartridge shares the 550E name for slot boards. This page covers the socketed package as primary. The chip supports MMX and SSE.

Balanced entry clocks with a tiny envelope suit Socket 370 value towers. The 5.5x half-ratio needs an exact BIOS string. That is why the 550E shipped in budget home boxes.

Socket and motherboard compatibility

The 550E fits Socket 370 value desktops with Coppermine support. It needs a 370-pin board with a 100 MHz bus and a BIOS that lists Pentium III 550E. The Socket vs chipset: what decides whether a CPU works guide covers pairing rules.

Value SDRAM towers are the natural match. Boards listing the 550E accept the chip with a 14.5 W cooler. Slot 1 boards take the cartridge twin.

Memory, PCIe and cooling

Memory is SDRAM through the board chipset, matched to the board sockets. The CPU has no memory controller. Value boards commonly run PC100 pairs.

A 100 MHz front side bus ties the CPU to the chipset, while AGP and PCI hang off the chipset. No PCIe lanes originate on the die. Cooling uses the Socket 370 lug clip with a 14.5 W cooler.

Upgrade paths

On the same socket, a Pentium III 600E on the same support list adds 50 MHz. A 500E drops 50 MHz at 13.2 W.

A move to Tualatin needs a Tualatin-ready board. The Socket 370 page lists the range. Note: the queue row lists 15 W; this page uses the verified 14.5 W.